Green Car Reports is carrying the story that the California New Car Dealers Association (CNCDA) has written a sharply worded letter to the California state Department of Motor Vehicles, accusing Tesla Motors of engaging "in a long-term advertising strategy to mislead consumers." The complaint is centered on the pricing calculator featured on Tesla Motors' website, which purports to give an "effective monthly cost" of owning a Tesla Model S.

The CNCDA's nine-page letter lists about a dozen specific complaints with Tesla Motors' "True Cost of Ownership" page, most of which fall into two broad categories: savings that are calculated using outside credits or assumptions, and savings that are based on difficult-to-quantify or difficult-to-achieve metrics. For example, the site displays a price for its vehicles that includes the $7,500 federal Plug-In Electric Drive Vehicle Credit, it adds monthly cost offsets based on the money a Model S owner will get when they eventually sell the car, and it adds monthly cost offsets based on time saved by using a carpool lane and not sitting at gas stations filling up. The CNCDA also takes issue with the "Electricity vs. Gasoline" savings calculator.

To be sure, some of those cost offsets sound a little dubious, and it's obviously in Tesla's best interests to make buying a Model S as attractive as possible. The CNCDA's complaints don't necessarily appear to be that Tesla is offering this information, but rather that it appears to be presenting to consumers a modified per-month cost that includes factors it deems specious—or that it believes violate automobile advertising laws. Much of the letter is concerned with calling out specific California statutes that the CNCDA alleges Tesla is violating.

Some of the claims of the CNCDA are particularly puzzling—for example, page six of the letter includes this allegation:

a. The tax credit is completely irrelevant to the purchase price for the Model S. Whether the customer never applies for the credit, has insufficient tax liability to claim the full tax credit, or can claim the full credit, the tax credit has no bearing on the purchase price of the Model S.

b. Last year, the Congressional Budget Office studied the efficacy of the federal tax credit for electric vehicles and concluded that only 20% of potential tax filers have the tax liability sufficient to qualify for the full $7,500 tax credit. By including the tax credit in the advertised price quote for the vehicle, Tesla is misleading 80% of the population of the actual purchase price of the vehicle, even net of the federal tax credit.

The cited study, available here, correctly points out that it requires a federal tax liability of at least $7,500 to receive the full $7,500 credit, and some quick and dirty calculation shows that a married couple filing jointly would need a combined household income of $76,000 or more to hit that mark.

Enlarge/ First take the plank out of your own eye, and then you will see clearly to remove the speck from your brother's eye.

There are two obvious problems with the CNCDA's complaint. First, Tesla Model S prices start at over $70,000, so buyers are likely to be high earners. Second, and far more egregiously, other car manufacturers show the same savings on their websites. Chevrolet, for example, advertises an MSRP of $26,685 for their electric Volt, with fine print immediately next to the price that says, "Price after tax savings. Net price shown includes the full $7,500 tax credit." Even more egregious is that the Volt is targeted at a much less-affluent buyer than Tesla's offerings, so Volt buyers are statistically more likely to not qualify for the full credit.

Ultimately, the CNCDA's letter is the latest shot fired in a much larger war against Tesla's disruptive approach to selling vehicles. It strikes us as particularly ludicrous to see an association of car dealers calling out a car manufacturer for what it sees as deceptive pricing practices, considering the lengths car dealerships have been accused of going to disguise and distort the same pricing information.

Lee Hutchinson
Lee is the Senior Technology Editor at Ars and oversees gadget, automotive, IT, and culture content. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX. Emaillee.hutchinson@arstechnica.com//Twitter@Lee_Ars